public inbox for linux-arm-kernel@lists.infradead.org 
 help / color / mirror / Atom feed
From: Mauro Carvalho Chehab <mchehab@kernel•org>
To: Paul Kocialkowski <paul.kocialkowski@bootlin•com>
Cc: Nicolas Dufresne <nicolas@ndufresne•ca>,
	Jernej Skrabec <jernej.skrabec@siol•net>,
	Jonas Karlman <jonas@kwiboo•se>, Chen-Yu Tsai <wens@csie•org>,
	Maxime Ripard <mripard@bootlin•com>,
	linux-kernel@vger•kernel.org, Hans Verkuil <hverkuil@xs4all•nl>,
	linux-sunxi@googlegroups•com,
	Thomas Petazzoni <thomas.petazzoni@bootlin•com>,
	Tomasz Figa <tfiga@chromium•org>,
	Ezequiel Garcia <ezequiel@collabora•com>,
	linux-arm-kernel@lists•infradead.org,
	linux-media@vger•kernel.org
Subject: Re: [PATCH v8 3/3] media: cedrus: Add HEVC/H.265 decoding support
Date: Thu, 17 Oct 2019 09:57:51 -0300	[thread overview]
Message-ID: <20191017095751.5a229051@coco.lan> (raw)
In-Reply-To: <20190927143411.141526-4-paul.kocialkowski@bootlin.com>

Em Fri, 27 Sep 2019 16:34:11 +0200
Paul Kocialkowski <paul.kocialkowski@bootlin•com> escreveu:

> This introduces support for HEVC/H.265 to the Cedrus VPU driver, with
> both uni-directional and bi-directional prediction modes supported.
> 
> Field-coded (interlaced) pictures, custom quantization matrices and
> 10-bit output are not supported at this point.
> 
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin•com>
> ---

...

> +		unsigned int ctb_size_luma =
> +			1 << log2_max_luma_coding_block_size;

Shifts like this is a little scary. "1" constant is signed. So, if
log2_max_luma_coding_block_size is 31, the above logic has undefined
behavior. Different archs and C compilers may handle it on different
ways.

> +#define VE_DEC_H265_LOW_ADDR_PRIMARY_CHROMA(a) \
> +	(((a) << 24) & GENMASK(31, 24))

Same applies here and on other similar macros. You need to enforce
(a) to be unsigned, as otherwise the behavior is undefined.

Btw, this is a recurrent pattern on this file. I would define a
macro, e. g. something like:

	#define MASK_BITS_AND_SHIFT(v, high, low) \
		((UL(v) << low) & GENMASK(high, low))

And use it for all similar patterns here.

The best would be to include such macro at linux/bits.h, although some
upstream discussion is required.

So, for now, let's add it at this header file, but work upstream
to have it merged there.


Thanks,
Mauro

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists•infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2019-10-17 12:59 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-27 14:34 [PATCH v8 0/3] HEVC/H.265 stateless support for V4L2 and Cedrus Paul Kocialkowski
2019-09-27 14:34 ` [PATCH v8 1/3] media: v4l: Add definitions for HEVC stateless decoding Paul Kocialkowski
2019-09-27 14:34 ` [PATCH v8 2/3] media: pixfmt: Document the HEVC slice pixel format Paul Kocialkowski
2019-09-27 14:34 ` [PATCH v8 3/3] media: cedrus: Add HEVC/H.265 decoding support Paul Kocialkowski
2019-10-17 12:57   ` Mauro Carvalho Chehab [this message]
2019-10-22 12:40     ` Paul Kocialkowski
2019-10-22 13:17       ` Paul Kocialkowski
2019-10-22 13:37         ` Hans Verkuil
2019-10-22 14:01           ` Paul Kocialkowski
2019-10-22 14:02             ` Hans Verkuil
2019-10-08 21:48 ` [PATCH v8 0/3] HEVC/H.265 stateless support for V4L2 and Cedrus Jernej Škrabec
2019-10-09  7:12   ` Paul Kocialkowski

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191017095751.5a229051@coco.lan \
    --to=mchehab@kernel$(echo .)org \
    --cc=ezequiel@collabora$(echo .)com \
    --cc=hverkuil@xs4all$(echo .)nl \
    --cc=jernej.skrabec@siol$(echo .)net \
    --cc=jonas@kwiboo$(echo .)se \
    --cc=linux-arm-kernel@lists$(echo .)infradead.org \
    --cc=linux-kernel@vger$(echo .)kernel.org \
    --cc=linux-media@vger$(echo .)kernel.org \
    --cc=linux-sunxi@googlegroups$(echo .)com \
    --cc=mripard@bootlin$(echo .)com \
    --cc=nicolas@ndufresne$(echo .)ca \
    --cc=paul.kocialkowski@bootlin$(echo .)com \
    --cc=tfiga@chromium$(echo .)org \
    --cc=thomas.petazzoni@bootlin$(echo .)com \
    --cc=wens@csie$(echo .)org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox